1. Technical Field
The present disclosure relates to joints and hinges used to connect movable components of an electrosurgical instrument and, more particularly, to an electrically-insulative hinge for use in an electrosurgical jaw assembly, a bipolar forceps including an electrically-insulative hinge, and methods of jaw-assembly alignment using a fastened electrically-insulative hinge.
2. Discussion of Related Art
Electrosurgical instruments, such as electrosurgical forceps, have become widely used by surgeons. Electrosurgery involves application of high-frequency electrical current to a surgical site to cut, ablate, coagulate, cauterize or seal tissue.
The basic purpose of both monopolar and bipolar electrosurgery is to produce heat to achieve the desired tissue/clinical effect. In monopolar electrosurgery, devices use an instrument with a single, active electrode to deliver energy from an electrosurgical generator to tissue, and a patient return electrode or pad that is attached externally to the patient (e.g., a plate positioned on the patient's thigh or back) as the means to complete the electrical circuit between the electrosurgical generator and the patient. When the electrosurgical energy is applied, the energy travels from the active electrode, to the surgical site, through the patient and to the return electrode.
In bipolar electrosurgery, the electrosurgical device includes two electrodes that are located in proximity to one another for the application of current between their surfaces. Bipolar electrosurgical current travels from one electrode, through the intervening tissue to the other electrode to complete the electrical circuit. Bipolar instruments generally include end effectors, such as grippers, cutters, forceps, dissectors and the like.
Bipolar electrosurgical forceps utilize two generally opposing electrodes that are operably associated with the inner opposing surfaces of end effectors and that are both electrically coupled to an electrosurgical generator. Each electrode is charged to a different electric potential. By utilizing an electrosurgical forceps, a surgeon can utilize both clamping action and electrosurgical energy to cauterize, coagulate/desiccate and/or cut tissue and/or simply reduce or slow bleeding by controlling the intensity, frequency and duration of the electrosurgical energy applied to the tissue.
Typically, joints and hinges for use in electrosurgical instruments to connect movable components are formed from an electrically-insulative material to prevent electrical shorting between component parts and/or prevent the formation of alternate current paths through the instrument. As such, instrument designers have manufactured electrosurgical instruments that involve complex, rotating hinge configurations to isolate, insulate and/or control the electrosurgical active areas of the instrument.
Traditional metal hinge configurations generally include multiple, independent sub-assemblies. Typically, the sub-assemblies are overmolded with plastic material having high bond strength. These separately overmolded sub-assemblies are mechanically integrated and arranged in a series of manufacturing steps that often require tightly controlled, time-consuming processes to achieve proper jaw alignment. Additional steps are often undertaken to control other parameters associated with the rotational movement about the hinge, e.g., friction, torque, etc.